EP0666880B1 - Catalyst for the production of polyurethanes and/or polyureas - Google Patents

Description

The invention relates to catalysts for the production of Polyurethanes and / or polyureas and in particular for Production of such foams.

It is known that a variety of organic, organometallic and inorganic compounds as catalysts can be used to manufacture polyurethanes (J.H. Saunders and K.C. Frisch, Polyurethanes Chemistry and Technology, P. 73 ff, 1962). From the group of organic compounds is based on tertiary amines such as bis (dimethylaminoethyl) ether (US Pat 3,400,157), amino orthoesters (U.S. Patent 3 786 029) and β, β'-dimorpholinodiethyl ester (German Offenlegungsschrift 2 138 403). More catalytically active Substances can be derivatives of organic acids such as potassium acetate or be potassium 2-ethylhexanoate. Examples of metal catalysts are Sn (II) / Sn (IV) salts or Fe (III) salts (DE-Offenlegungsschrift 3 938 203).

The catalysts currently used have a large number of disadvantages. Amines such as bis (dimethylaminoethyl) ester or Triethylenediamine has a negative impact on the Laminating foils used from polyurethane foams Polyvinyl chloride, e.g. due to discoloration of the foils and impairment the mechanical properties, like the Elasticity of the foils (R.L. Zimmerman, T.H. Austin, J. Cell. Plast., 24 (3), 256-65, 1988). The cause of these effects is in the migration of the amine catalyst into the film too see. There they cause hydrochloric acid to split off from the Polymer. The resulting polyolefins lead to a Discoloration and to a higher degree of networking, which is a decrease which means elasticity and undesirable embrittlement leads.

If amine catalysts are used with the isocyanate group reactive substituents, those described above undesirable effects reduced in individual cases (R.L. Zimmerman, T.H. Austin, J. Cell. Plast., as above). However, there is complete freedom from discoloration and more complete Preservation of film properties not achieved (A. Christfreund, E. Huygens, B. Eling, Cell. Polym., 10 (6), 452-65, 1991 and R.G. Petrella, J.D. Tobias, J. of Cellular Plastics, 25, 421-40, 1989).

If one uses other than amine catalysts for the production of foamed polyurethane and / or polyureas occur also have serious disadvantages. This applies, for example for organometallic compounds such as dibutyltin dilaurate DBTL (C.B.G. Colvin, Cell. Polym., 11 (1), 29-56, 1992) with respect to the film discoloration.

Alkali or alkaline earth salts of carboxylic acids are used as catalysts known per se for polyurethane catalysis. GB 770,526 describes e.g. the implementation of tri-functional alkyds with Isocyanates in the presence of such catalysts to form polyurethanes. The catalysts for this include discloses: the sodium salt of acetic acid, succinic acid and lactic acid as well as the Potassium salt of acetic acid, citric acid, naphthenic acid and ethyl lactic acid.

EP-A-0 294 161 describes the reaction of polyols Isocyanates in the presence of catalysts to form polyurethanes. As Catalysts become alkali or alkaline earth salts of compounds of the type R-A-COOH, wherein R is an R'OCO-, R'COO- or R'O- group, A a divalent alkyl group and R 'one Represent alkyl group.

Another disadvantage is the use of metal salts of Carboxylic acids. It is known that in the manufacture of cellular polyurethane and / or polyureas the right one Catalytic control of the reaction of isocyanates with hydroxy-bearing groups, such as polyols or chain extenders, and the reaction of isocyanates with water from is essential. It is also known that metal salts of carboxylic acids such as potassium acetate is the driving reaction Catalyze isocyanate / water well (J. Bechara, J. Cell. Plast. (March / April) 103, 1979), but the important gelling reaction Isocyanate / polyol or chain extender insufficient catalyze.

In practice, with unbalanced catalysis, the and gelling reaction for the manufacture of the molded parts Polyurethane-back-foamed polyvinyl chloride important processing parameters like the cream or start time, the gel time and the climb time has not been reached. Potassium acetate causes as a catalyst, the setting of a technology sufficient Cream time. The gel time is far too short, though insufficient flow behavior of the polyurethane foam mass leads. Potassium 2-ethylhexanoate, however, allows also the setting of a cream time sufficient for the technique, however, too much leads to long gelling and rising times.

Another disadvantage of the metal salts of carboxylic acids is whose limited solvency in the production of cellular polyurethane and / or urea-suitable polyol formulations. These are also referred to as A components Formulations typically consist of one or more polyols, if necessary one or more chain extenders and cell stabilizers and water, and optionally other Aggregates and fillers. Such a mix is due to their non-polar character has only limited solvency against strongly polar compounds such as those mentioned above Salt. This leads to a partial or complete Precipitation of the above carboxylic acid salts what in turn leads to a sharp decrease in activity.

The invention has for its object new catalysts to develop for the production of polyurethanes and polyureas, which do not have the disadvantages mentioned above.

This object is achieved according to claim 1 by providing Catalysts consisting of alkali metal and alkaline earth metal salts dissolved by alkyl or alkenyl succinic acids.

The invention particularly relates to the use of these Compounds as catalysts for the production of cellular Polymers containing urethane and / or urea groups.

in welchen
R eine verzweigte oder unverzweigte Alkylgruppe mit 1 bis 30 Kohlenstoffatomen, eine verzweigte oder unverzweigte Alkenylgruppe mit 2 bis 30 Kohlenstoffatomen oder eine verzweigte oder unverzweigte Alkylether- oder Alkenylethergruppe mit 2 bis 30 Kohlenstoffatomen und 1 bis 6 Sauerstoffatomen bedeutet. M⁺ steht für ein Metallkation der ersten Hauptgruppe des Periodensystems und M⁺⁺ für ein Metallkation der zweiten Hauptgruppe des Periodensystems.The succinic acid compounds I and II provided for this have the following chemical structure:

in which
R represents a branched or unbranched alkyl group having 1 to 30 carbon atoms, a branched or unbranched alkenyl group having 2 to 30 carbon atoms or a branched or unbranched alkyl ether or alkenyl ether group having 2 to 30 carbon atoms and 1 to 6 oxygen atoms. M ⁺ stands for a metal cation of the first main group of the periodic table and M ⁺⁺ for a metal cation of the second main group of the periodic table.

steht R bevorzugt für eine verzweigte oder unverzweigte Alkyl-gruppe mit 1 bis 20, insbesondere 1 bis 10 Kohlenstoffatomen, eine verzweigte oder unverzweigte Alkenylgruppe mit 2 bis 20, insbesondere 2 bis 10 Kohlenstoffatomen, oder eine verzweigte oder unverzweigte Alkylether- oder Alkenylethergruppe mit 2 bis 20, insbesondere 2 bis 10 Kohlenstoffatomen und 1 bis 3 Sauerstoffatomen. M⁺ steht bevorzugt für das Natriumkation und das Kaliumkation. M⁺⁺ steht bevorzugt für das Calciumkation und das Magnesiumkation. Besonders bevorzugt sind das Kaliumkation für M⁺ und das Magnesiumkation für M⁺⁺. In the compounds of general formula I and II used according to the invention

R preferably represents a branched or unbranched alkyl group having 1 to 20, in particular 1 to 10 carbon atoms, a branched or unbranched alkenyl group having 2 to 20, in particular 2 to 10 carbon atoms, or a branched or unbranched alkyl ether or alkenyl ether group having 2 to 20, in particular 2 to 10 carbon atoms and 1 to 3 oxygen atoms. M ⁺ preferably stands for the sodium cation and the potassium cation. M ⁺⁺ preferably stands for the calcium cation and the magnesium cation. The potassium cation for M ⁺ and the magnesium cation for M ⁺⁺ are particularly preferred.

1 - die Katalysatoren besitzen eine ausreichend hohe Aktivität;

2 - die Katalysatoren in Polyurethan/Polyharnstoffsystemen zur Hinterschäumung von Polyvinylchloridfolien eingesetzt verursachen keinerlei Verfärbung und Beeinträchtigung der physikalischen Eigenschaften der Folien;

3 - Die Katalysatoren haben hohe Gelieraktivität und bewirken daher die in der Praxis geforderte hohe Zugfestigkeit des Schaums;

4 - die Katalysatoren sind in der Mischung aus Polyolen und weiteren Zuschlagstoffen löslich und lagerstabil;

5 - die Katalysatoren vermögen die Zellstruktur der Schäume vorteilhaft zu beeinflussen.

The catalysts and mixtures thereof according to the invention have surprising properties as catalysts:

1 - the catalysts have a sufficiently high activity;

2 - the catalysts used in polyurethane / polyurea systems for the back-foaming of polyvinyl chloride films do not cause any discolouration or impairment of the physical properties of the films;

3 - The catalysts have high gelling activity and therefore bring about the high tensile strength of the foam required in practice;

4 - the catalysts are soluble in the mixture of polyols and other additives and have a long shelf life;

5 - the catalysts can have an advantageous effect on the cellular structure of the foams.

The catalysts of the invention are through the implementation appropriately substituted succinic acids or their Anhydrides with hydroxide salts of the metals of the first or second main group available.

Examples of suitable alkyl or alkenyl succinic acids or anhydrides are
(Diisobutenyl) succinic acid / anhydride, n-hexenylsuccinic acid / anhydride, n-dodecenylsuccinic acid / anhydride, (tetrapropenyl) succinic acid / anhydride, (polyisobutenyl) succinic acid / anhydride, (diisobutyl) succinic acid / anhydride, n-hexylberberic acid, n-hexylberber anhydride, (tetrapropyl) succinic acid / anhydride, (polyisobutyl) succinic acid / anhydride.

Examples of suitable hydroxide salts of the metals are Lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, Calcium hydroxide and barium hydroxide.

The claimed compounds are particularly suitable for Production of cellular polyurethanes, the inventive Catalysts alone, in combination with each other or with for the production of polyurethanes and polyureas suitable commercially available catalysts can be used can. Such commercial catalysts can from Group of tertiary amines, phosphorus compounds and metal compounds come.

The following amine catalysts may be mentioned as examples of commercially available catalysts:
Triethylenediamine, bis (dimethylaminoethyl) ether, dimethylcyclohexylamine, dimethylbenzylamine, dimethylethanolamine, N-methylmorpholine, N-ethylmorpholine, dimorpholinodiethyl ether, tetramethylhexamethylenediamine, 2-methyl-2-azanorborane, 2- (hydroxyethoxyethyl) -2-azinoorbornane ) ethanol, 3-dimethylaminopropyl-diisopropanolamine, bis (3-dimethylaminopropyl) -isopropanolamine and 2-dimethylaminoethyl-3-dimethylaminopropyl ether.

The following are mentioned as examples of commercially available metal catalysts:
Metal salts, preferably tin, a carboxylic acid and mixed alkyl and carboxylic acid derivatives of a metal. For example, dibutyltin dilaurate, dibutyltin diacetate, diethyltin diacetate, tin dioctoate and mixtures thereof can be used.

It is also possible to add a foam stabilizer in particular those from the class of the silanes or siloxanes (U.S. Patent 3,194,773).

The following polyisocyanates can be used, for example, to produce foamed polyurethanes using the catalysts according to the invention:
Hexamethylene diisocyanate, phenylene diisocyanate, tolylene diisocyanate, isophorone diisocyanate, naphthylene diisocyanate and 4,4'-diphenylmethane diisocyanate. 2,4-tolylene diisocyanate or 2,6-tolylene diisocyanate and mixtures thereof are particularly suitable. Other suitable polyisocyanates are commercially available mixtures known as "crude-MDI", which contain about 60% of the 4,4'-diphenylmethane diisocyanate and isomeric or analogous higher molecular weight polyisocyanates. Mixtures of tolylene diisocyanate and 4,4'-diphenylmethane diisocyanate and the polyisocyanates known as "crude MDI" are also particularly suitable. Likewise suitable are "prepolymers" of the above-mentioned polyisocyanates, consisting of the reaction products of polyisocyanates and polyether or polyester polyols.

The polyol component that is reactive with the polyisocyanates can be a polyester polyol or a polyether polyol. Suitable Polyols are e.g. Polyalkylene or polyester polyols. Particularly suitable polyalkylene polyols include polyalkylene oxide polymers, such as polyethylene oxide and polypropylene oxide polymers as well as mixed polymerized polyethylene and polypropylene oxide polymers. Starting compounds for such polyalkylene polyols are, for example, ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, Diethylene glycol, dipropylene glycol, pentaerithritol, Glycerin, diglycerin, trimethylolpropane, cyclohexanediol, Sucrose and sucrose.

Suitable polyester polyols include the reaction products Dicarboxylic acids with an excess of diols e.g. Adipic acid with ethylene glycol or butanediol or the reaction products from lactones with an excess of a diol, e.g. Caprolactone and propylene glycol.

The catalysts of the invention are also in combination can be used with other catalysts, especially in combinations with tertiary amines, preferably those which at least one substituent with at least one opposite of the isocyanate group contains reactive hydrogen. Especially dimethylethanolamine, dimethylaminopropylamine are preferred, 2- (hydroxyethoxyethyl) -2-azanorbornane, 2- (2-dimethylaminoethoxy) ethanol and 3-dimethylaminopropyl-diisopropanolamine. Combinations with metal catalysts are also possible suitable, preferably tin compounds of a carboxylic acid and / or mixed alkyl and carboxylic acid derivatives of tin. Dibutyltin dilaurate, dibutyltin diacetate, Diethyltin diacetate, tin dioctoate and mixtures from that.

The following examples serve to illustrate the invention.

example 1 Tetrapropenyl succinic acid dipotassium salt

16 g of potassium hydroxide, 53.04 g of ethylene glycol and 37.04 g of tetrapropenyl succinic anhydride were transferred to a glass flask. The mixture was stirred at 100 ° C for two hours.
Yield: 103 g = 97.1% of theory. Theory.
The catalyst solution obtained is hygroscopic. The water content is therefore 3.1% compared to 2.5% of theory. Theory.

Example 2 Hexenyl succinic acid dipotassium salt

16 g of potassium hydroxide, 41.5 g of ethylene glycol and 25.5 g of hexenylsuccinic anhydride are transferred to a glass flask. The mixture is stirred at 100 ° C for two hours.
Yield: 78.9 g = 98.0% of theory. Theory.
The resulting catalyst solution is hygroscopic.

Example 3

Use of the compounds described in Examples 1 and 2 as catalysts in the production of flexible polyether foam (TDI / MDI cold foam formulation).

The flexible polyether foam was produced after Manual mixing process. It was the A component, she contained a suitable polyol, a foam stabilizer, the catalyst according to the invention and water as blowing agent, with a high-performance stirrer at 5000 rpm 30 s touched. Then the required amount of a suitable one was given Add polyisocyanates, stirred for 3 s at 5000 rpm and poured the foamable mixture into a cube shape (Edge length 27 cm). It was by means of an ultrasound probe coupled measurement data acquisition system Rise curves recorded. From the climbing curves thus obtained could the cream times as well as the rise times and rise heights be determined.

The following recipe was used for foaming: Polyol (a) 100.0 g Diethanolamine 1.00 g Isocyanate (b) 37.8 g water 3.0 g Stabilizer (c) 0.8 g catalyst see table I index 100 (a) branched polyol with an OH number of 26-30 and an average molecular weight of 6000 g / mol (b) Mixture of 80% by weight toluene diisocyanate (TDI) with 80% by weight 2,4-isomers and 20% by weight 2,6-isomers and 20% by weight methylene diphenyl diisocyanate (MDI) (c) polyether siloxane Characteristic values of foaming catalyst amount Cream time Gel time, beginning Gel time, end Rise time density temperature [pphp] [s] [s] [s] [s] [kg / m ³ ] [° C] I (1) 1.5 6 35 42 116 34.3 22 II (2) 1.5 6 29 35 100 33.8 22 III (3) 1.5 7 20th 24th 52 35.1 22 IV (4) 1.5 5 51 69 249 32.3 22 Influence of the catalyst on the tensile strength (measured according to DIN 53571) of the foam catalyst Tensile strength [kPa] I. 90 II 90 III 52 IV 72

It can be seen from Table II that, in particular, those for the Strain and durability of the foamed components in particular decisive tensile strength when using the invention Catalysts I and II compared to the catalysts the prior art is particularly improved.

Example 4

Use of the compounds described in Examples 1 and 2 as catalysts in the production of flexible polyether foam (all-MDI cold foam formulation).

The flexible polyether foam was produced after Manual mixing process. It was the A component, she contained a suitable polyol, a foam stabilizer, the catalyst according to the invention and water as blowing agent, stirred with a high-performance stirrer at 5000 rpm for 30 s. Then the required amount of a suitable one was given Add polyisocyanates, stirred for 3 s at 5000 rpm and poured the foamable mixture into a cube shape (Edge length 27 cm). It was by means of an ultrasound probe coupled measurement data acquisition system Rise curves recorded. From the climbing curves thus obtained could the cream times as well as the rise times and rise heights be determined.

The following recipe was used for foaming: Polyol 100.0 g Diethanolamine 1.00 g Isocyanate 52.0 g water 3.0 g stabilizer 0.8 g catalyst see table III index 100 Characteristic values of foaming catalyst amount Cream time Gel time, beginning Gel time, end Rise time density temperature [pphp] [s] [s] [s] [s] [kg / m ³ ] [° C] I (1) 1.5 13 55 112 265 41.1 20th II (2) 1.5 12th 48 94 202 41.4 20th III (3) 1.5 15 36 55 151 42.5 20th IV (4) 1.5 14 92 225 350 38.1 20th Influence of the catalyst on the tensile strength (measured according to DIN 53571) of the foam catalyst Tensile strength [kPa] I. 121 II 131 III 100 IV 107

It can be seen from Table IV that, in particular, those for the Strain and durability of the foamed components in particular decisive tensile strength when using the invention Catalysts I and II compared to Prior art catalysts have been particularly improved becomes.

Claims (10)

1. A method for producing polyurethanes and/or polyureas by reacting at least one polyisocyanate with at least one polyol in the presence of a catalyst composition and optionally a foam stabilizer, characterized in that a catalyst composition is used which contains or consists of one or more succinic acid compounds with the general formulas I and/or II

   

   where R represents a branched or unbranched alkyl group with 1 to 30 carbon atoms, a branched or unbranched alkenyl group with 2 to 30 carbon atoms or a branched or unbranched alkyl ether or alkenyl ether group with 2 to 30 carbon atoms and 1 to 6 oxygen atoms, M⁺ a metal cation of the first main group of the periodic system and M⁺⁺ a metal cation of the second main group of the periodic system.
2. The method of claim 1, wherein in Formula I and Formula II R represents an alkyl group with 1 to 20 carbon atoms, an alkenyl group with 2 to 20 carbon atoms or an alkyl ether or alkenyl ether group with 2 to 20 carbon atoms and 1 to 3 oxygen atoms.
3. The method of claim 1, wherein in Formula I and Formula II R represents an alkyl group with 1 to 10 carbon atoms or an alkenyl group with 2 to 10 carbon atoms.
4. The method of any of claims 1 to 3, wherein in Formula I and Formula II M⁺ represents the sodium cation or the potassium cation and M⁺⁺ the calcium cation or the magnesium cation.
5. , The method of any of claims 1 to 3, wherein in Formula I M⁺ represents the potassium cation.
6. The method of any of claims 1 to 3, wherein in Formula II M⁺⁺ represents the magnesium cation.
7. The method of any of claims 1 to 5, wherein the catalyst composition used is one or more succinic acid compounds with the general Formula I.
8. The method of any of claims 1 to 4 or 6, wherein the catalyst composition used is one or more succinic acid compounds with the general Formula II.
9. The method of either of claims 7 and 8, wherein the catalyst composition used is one or more succinic acid compounds with Formula I or II whose residue R is a tetrapropenyl or hexenyl residue.
10. A catalyst composition according to any of claims 1 to 9.